KVM: MMU: Topup the mmu memory preallocation caches before emulating an insn

Emulation may cause a shadow pte to be instantiated, which requires
memory resources.  Make sure the caches are filled to avoid an oops.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/kvm/mmu.c b/drivers/kvm/mmu.c
index ace3cb86214b..9be54a5e858e 100644
--- a/drivers/kvm/mmu.c
+++ b/drivers/kvm/mmu.c
@@ -1362,6 +1362,10 @@ int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t cr2, u32 error_code)
                 goto out;
         }
 
+        r = mmu_topup_memory_caches(vcpu);
+        if (r)
+                goto out;
+
         er = emulate_instruction(vcpu, vcpu->run, cr2, error_code, 0);
         mutex_unlock(&vcpu->kvm->lock);